Conventionally, dressings for the treatment or prevention of wounds or pressure sores or even unbroken skin are essentially flat dressings which are sufficiently mouldable to be applied to flat or slightly curved areas of the body. Such flat dressings are not very suitable for applying on protruding parts of the body or joints such as elbows, heels or especially the tips of fingers or toes or parts of the body having a very pronounced curvature such as the interdigital area as they often wrinkle and focus stresses in the dressing often causing slipping of the adhesive and unintended detachment of the dressing.
Published European patent application No. EP 0 676 183 A1 discloses conformable adhesive bandages which are stated to be extremely conformable, and yet resilient enough to maintain its shape after being subjected to forces caused by movement of the wearer. Furthermore it is stated that the recovered energy of the bandage disclosed in EP 0 676 183 A1 should be relatively high, so as to assure that the bandage will not permanently deform in use. Such recovered energy built-in into a dressing or bandage will inevitably try to retract it to its original shape if stretched during use and expose the skin to a significant stress which will cause nuisance to the user.
U.S. Pat. No. 4,436,700 discloses pressure sensitive adhesive sheet materials, which are stated to be conformable and having viscoelastic properties similar to human skin. Furthermore it is stated, that the materials exhibit stress relaxation with time, having relaxation properties to recover to near original unstressed length, when all stress is removed.
Published European patent application No. EP 0 457 977 A1 discloses a wound dressing comprising a pad of soft polyurethane foam, one surface layer of which is hydrophilic and a backing layer of which is hydrophobic and a sheet or strip of a soft conformable polyether foam having an adhesive on one surface thereof, said dressing showing a sufficient elasticity to readily conform for extended periods of time to difficult areas such as elbow joints and knee joints.
U.S. Pat. No. 1,741,949 discloses an elastic polyetherester nonwoven web formed by meltblowing fibres composed of a polyester.
A liquid plaster in the form of a solution of a polymer in ethyl acetate is known under the trade mark Nobecutan.RTM.. Such a plaster will naturally conform to the area onto which it is applied but is highly unsuitable for application on broken or irritated skin due to the content of ethyl acetate giving a severe local irritation.
Until now no reference discloses dressings being able to adhere to the skin, said dressing being flexible and mouldable so as to adapt to the contour of the part of the body to be covered and said dressing adhering to the skin and being able to adapt to and follow the movements of joints such as finger joints without exposing the skin to a significant stress after application and being applicable directly on broken or irritated skin without unpleasant feeling.
One object of the invention is to provide a dressing being mouldable and flexible so as to be able to adapt to the contour of the part of the body to be covered and said dressing adhering to the skin and being able to adapt to and follow the movements of the skin or joints such as finger joints. Such dressing will be suitable as e.g. a finger tip or toe tip dressing or a dressing suitable for use on joints and even in the interdigital area on the hand or foot.
Another object of the invention is to provide a dressing which may prevent e.g. wearing or abrasion damages, e.g. on heels or elbows, said dressing being provided with a surface which may be adapted to the environment in which the dressing is to be used giving a longer effective time of use for the dressing between the change of the dressing.
A further object of the invention is to provide a dressing which comprises emollients or an active constituent e.g. retinoids for treating or preventing formation of psoriasis, eczema, callous skin, corns, insect bites, acne or blisters.
A still further object of the invention is to provide processes for the preparation of such dressings.